Henry



(No Model.)

` H. C. JOHNSON & F. M. MGMILLAN.

PIRE PROOP SAFE. No. 261,461 Ptented July 18, 1882 /l/l//l/ I/l//ll/ /I/I/M/l//ll/ N. PETERS, PmuLM nn Washington. n. c.

i UNITED -STATES PATENT OFFICE.

HENnY c. ioHNsoN'AND FRANCIS M. MCMILLAN, OF WASHNGTON, D. o.

FlRE-PROOF SAFEL SPECIFICATION forming part of Letters Patent No. 261,461, dated July 18, 1882.

i Application filed April 6, 1882. (No model.)

To all whom it may concm Be it known that we, HENRY O. JOHNSON and FRANCIS M. MOMILLAN, of Washington, in the District of Columbia, have invented certain .[mprovements in Fire-P'oof Safes, of which the following is a specification.

'Th-is invention relates to fire-proof safes and it consists in providngthe safe with avessel or receiver charged with carbonic-acid gas or other highly-compressible fluid reduced to a liquid form, and provided with a valve which is held normally closed by a fusible retaining device, preferably on the outside of the safe, so as to be exposed to the atmosphere of the room in which the safe stands.

The details to be adopted in carrying out the invention may be varied considerahly without departing from its limits, the essential feature of the invention consisting in providing a vessel charged with the liquid gas with a valve from or through which the liquefied gas may escape'in a small thread-like stream into the interio'r of the safe, and by its sudden expansion produce intense cold, thus counteracting and neutralizing the heat which may find its way through the walls of the safe,while at the same time actually preventing combustion. i In the accompanying drawings, Figure lrepresents a safe provided with the improvement; and Fig. 2, a sectional view, showing the construction and ar'rangenent of parts.

A represents a safe,\vhich may be ot' special orordinary Construction, and B the gas-receiver, charged with the liquefied gas and provided with an outlet-val ve, (J, the stem a of which is tapered down to a fine needle-like point, and closes a small outlet-passage, b. 4 The Valvestem a is pressed and held to its seat by a le'- ver, c,which is held down upon the head ofthe stem by astrong wire or rod, d, passingthrough the bottom or wall ot' the safeandseeured by a fusible nut or block, e,which may be screwed upon the wire or held in place thercon by riveting the end of the wire down upon the outer face of the nut or block, as shown. The block -or nut e will be made ot' a metal alloy or composition capableot'securely retainingthe wire, but which will fuse at a given temperature, preferably a little higher than would ever naturally occur in the roon in which the safe is located. 4

' be sufficiently small to cause the gas to escape slowly and in a very fine stream, thus securing a long-continning gradnal discharge, which 6o may require a number of days to empty the receiver. The gas vescaping through the joints around the door will materially aid in putting out the fire.

Fnsible alloys and compouds are so common and well known that it is unnecessary to state their composition, though we prefer an alloyof tin, lead, bismuth, and mercury,in the following proportions: tin, five part-s lead, three parts; bismuth, three parts; 'mercury, 7o three parts, because ofits low melting-point 122 Fahrenheit. i

The alloy or compound may be varied orits proportions changed to alter the melting point.

Thc'recever may hebnilt into the wall of the 7 safe or placed inside, and the fusible nut or block may also be inside or outside, but pret'- erably outside.

We are aware that vessels containing acids have been placed within safes and designed to discharge their contents into or upon soda or other snbstance,which, acted upon by the acid, would prodnce carbonic-acid gas; but our invention difi'ers from these, in that we cfi'ect a* ref-igeration of the int'erior of the safe, the extinguishing property of the gas being purely incidental thereto. i

We are aware that'it is not new to provide a safe with chambers or vessels charged with liquefied gas, and provided with fusible plugs 0 which should melt and permitthe gas to escape outside ot' the safe in case the temperature reached a given height. Our invention difl'ers 'from this and from i the use of water or steam chambers, in that we efl'ect a refrigeration of the interier of the safe, which is additional to the ordinary protection of the lining or filling ot' the walls. The eft'ect upon combustion is a mere incidental matter, and is not a matter of importance, the refrigerative or cooling efect being solely reiied upon by us, and this being possible only when the discharge is within the safe.

Having thue` described our invention, what we claim is 1. In conhination with a safe, a gas-receiver inside of the safe, provided with an escape-valve opening into the safe, a lever hearing upon the valve and serving to hold the plug to its seat, and a fnsibie device adapted and arranged to hold the lever down upon the valve until a given tem peratnre is reached, and then to release the iever and valve, as explained. 

